Where Is The 12V Battery On A Gen5 HEV?

Discussion in 'Gen 5 Prius Main Forum' started by VelvetFoot, Sep 24, 2025 at 7:18 AM.

  1. Gokhan

    Gokhan Senior Member

    Joined:
    Oct 5, 2008
    5,916
    2,337
    0
    Location:
    Paramount CA
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Oh, the XLE pic above is an XLE AWD pic then, and I see the screw hole now, thanks.
     
  2. RandyPete

    RandyPete Active Member

    Joined:
    Apr 1, 2021
    397
    163
    0
    Location:
    Santa Margarita, CA, USA
    Vehicle:
    2024 Prius Prime
    Model:
    XSE
    Which maintainer brand. How many amps is it rated for ? How long do you leave the car sit before starting it ?
     
  3. Gokhan

    Gokhan Senior Member

    Joined:
    Oct 5, 2008
    5,916
    2,337
    0
    Location:
    Paramount CA
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    You are worrying unnecessarily, as neither Gen 4 nor Gen 5 has any real 12-V battery issues. Every now and then, a few people have isolated problems arising from such as the new car sitting in the dealer lot for too long before purchased, car not being driven frequently or long enough, using third-party accessories, using the accessory mode, unauthorized modifications, etc.

    Occasionally using a battery maintainer is a good idea. You don't need to permanently install it. Using it every few months is typically enough, also of course, always using it when the car is not regularly driven. Any Noco Genius will do. The 12-V-battery-management system doesn’t like to fully charge the 12-V battery; therefore, occasionally fully charging it using a battery maintainer will extend its life and/or reduce the chances of a low-charge battery.
     
    VelvetFoot likes this.
  4. KCWhitney

    KCWhitney Active Member

    Joined:
    Apr 8, 2017
    124
    114
    0
    Location:
    Connecticut
    Vehicle:
    2025 Prius Plug-in
    Model:
    XLE
    I believe it is called BatteryTender. I told my dealer I wanted to maintain the battery, now that the car will be getting much less usage. and this is what they sold me. I don't know the rating off-hand. I have let it sit for at least four months, maybe longer, expecting the tender to do it's job. I have it wrapped, and it is a pain to unwrap it, just to charge the battery, which should be done through the device that was built to do just that.
     
  5. Gokhan

    Gokhan Senior Member

    Joined:
    Oct 5, 2008
    5,916
    2,337
    0
    Location:
    Paramount CA
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Get the Noco Genius. You can get the cheapest, 1-ampere one. It safely charges the Gen 4/Gen 5 12-V battery for about two days about twice a week, repeating the charge/standby cycle indefinitely according to the battery voltage, when plugged in.
     
  6. Paul Gregory

    Paul Gregory Senior Member

    Joined:
    Dec 9, 2022
    1,969
    500
    0
    Location:
    Alberta
    Vehicle:
    2024 Prius Prime
    Model:
    XSE
    My mechanic says they won't even tell you where a fuse is located,
    because they want you to pay the dealer to change it.
     
  7. VelvetFoot

    VelvetFoot Junior Member

    Joined:
    Sep 17, 2025
    77
    18
    0
    Location:
    New York State
    Vehicle:
    2025 Prius
    Model:
    LE
    Oy. But do they have an espresso machine in the customer waiting area like my MINI (BMW) dealer?
     
  8. Paul Gregory

    Paul Gregory Senior Member

    Joined:
    Dec 9, 2022
    1,969
    500
    0
    Location:
    Alberta
    Vehicle:
    2024 Prius Prime
    Model:
    XSE
    My dealer has a soda machine with no prices indicated. You have to use your card to find out that you just paid $5 for a can of Coke.

    This is in keeping with the predatory attitude I've experienced there since day one.
     
    #48 Paul Gregory, Sep 27, 2025 at 10:26 AM
    Last edited: Sep 27, 2025 at 11:36 AM
    VelvetFoot likes this.
  9. KMO

    KMO Senior Member

    Joined:
    Apr 15, 2004
    1,883
    643
    0
    Location:
    Finland
    Vehicle:
    2023 Prius Prime
    Model:
    N/A
  10. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    27,063
    17,746
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Good to know—I won't spoil the plot twist on p. 452.
     
    VelvetFoot likes this.